A man told police voices in his head made him commit a robbery Wednesday night. Aaron D. Williams, 31, was arrested for robbing the Village Pantry on North Meridian Street in Greenwood. He told police he has a mental disorder and is on medication for it. According to police, Williams used a large kitchen knife to hold up the store. Police pulled him over a short time later based on a description of his car and found a bag of money, cigarettes and the knife. Williams was taken to the Johnson County Jail and also was charged with two other robberies in the Greenwood area: a Red Roof Inn in January and another Village Pantry in April.